/*
- * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
 
 package java.lang;
 
-import java.io.IOException;
+import java.lang.ProcessBuilder.Redirect;
+import java.io.BufferedInputStream;
+import java.io.BufferedOutputStream;
+import java.io.ByteArrayInputStream;
+import java.io.FileDescriptor;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
-import java.lang.ProcessBuilder.Redirect;
-import java.lang.ProcessBuilder.Redirect;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.Arrays;
+import java.util.EnumSet;
+import java.util.Locale;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
+import java.security.AccessController;
+import static java.security.AccessController.doPrivileged;
+import java.security.PrivilegedAction;
+import java.security.PrivilegedActionException;
+import java.security.PrivilegedExceptionAction;
+import java.util.Properties;
+import jdk.internal.access.JavaIOFileDescriptorAccess;
+import jdk.internal.access.SharedSecrets;
+import jdk.internal.util.StaticProperty;
+import sun.security.action.GetPropertyAction;
 
 /**
- * This class is for the exclusive use of ProcessBuilder.start() to
- * create new processes.
+ * java.lang.Process subclass in the UNIX environment.
  *
+ * @author Mario Wolczko and Ross Knippel.
+ * @author Konstantin Kladko (ported to Linux and Bsd)
  * @author Martin Buchholz
+ * @author Volker Simonis (ported to AIX)
  * @since   1.5
  */
-final class ProcessImpl {
-    private static final sun.misc.JavaIOFileDescriptorAccess fdAccess
-        = sun.misc.SharedSecrets.getJavaIOFileDescriptorAccess();
+final class ProcessImpl extends Process {
+    private static final JavaIOFileDescriptorAccess fdAccess
+        = SharedSecrets.getJavaIOFileDescriptorAccess();
 
-    private ProcessImpl() {}    // Not instantiable
+    // Linux platforms support a normal (non-forcible) kill signal.
+    static final boolean SUPPORTS_NORMAL_TERMINATION = true;
+
+    private final int pid;
+    private final ProcessHandleImpl processHandle;
+    private int exitcode;
+    private boolean hasExited;
+
+    private /* final */ OutputStream stdin;
+    private /* final */ InputStream  stdout;
+    private /* final */ InputStream  stderr;
+
+    // only used on Solaris
+    private /* final */ DeferredCloseInputStream stdout_inner_stream;
+
+    private static enum LaunchMechanism {
+        // order IS important!
+        FORK,
+        POSIX_SPAWN,
+        VFORK
+    }
+
+    private static enum Platform {
+
+        LINUX(LaunchMechanism.VFORK, LaunchMechanism.POSIX_SPAWN, LaunchMechanism.FORK),
+
+        BSD(LaunchMechanism.POSIX_SPAWN, LaunchMechanism.FORK),
+
+        SOLARIS(LaunchMechanism.POSIX_SPAWN, LaunchMechanism.FORK),
+
+        AIX(LaunchMechanism.POSIX_SPAWN, LaunchMechanism.FORK);
+
+        final LaunchMechanism defaultLaunchMechanism;
+        final Set<LaunchMechanism> validLaunchMechanisms;
+
+        Platform(LaunchMechanism ... launchMechanisms) {
+            this.defaultLaunchMechanism = launchMechanisms[0];
+            this.validLaunchMechanisms =
+                EnumSet.copyOf(Arrays.asList(launchMechanisms));
+        }
+
+        @SuppressWarnings("fallthrough")
+        private String helperPath(String javahome, String osArch) {
+            switch (this) {
+                case SOLARIS:
+                    // fall through...
+                case LINUX:
+                case AIX:
+                case BSD:
+                    return javahome + "/lib/jspawnhelper";
+
+                default:
+                    throw new AssertionError("Unsupported platform: " + this);
+            }
+        }
+
+        String helperPath() {
+            Properties props = GetPropertyAction.privilegedGetProperties();
+            return helperPath(StaticProperty.javaHome(),
+                              props.getProperty("os.arch"));
+        }
+
+        LaunchMechanism launchMechanism() {
+            return AccessController.doPrivileged(
+                (PrivilegedAction<LaunchMechanism>) () -> {
+                    String s = System.getProperty(
+                        "jdk.lang.Process.launchMechanism");
+                    LaunchMechanism lm;
+                    if (s == null) {
+                        lm = defaultLaunchMechanism;
+                        s = lm.name().toLowerCase(Locale.ENGLISH);
+                    } else {
+                        try {
+                            lm = LaunchMechanism.valueOf(
+                                s.toUpperCase(Locale.ENGLISH));
+                        } catch (IllegalArgumentException e) {
+                            lm = null;
+                        }
+                    }
+                    if (lm == null || !validLaunchMechanisms.contains(lm)) {
+                        throw new Error(
+                            s + " is not a supported " +
+                            "process launch mechanism on this platform."
+                        );
+                    }
+                    return lm;
+                }
+            );
+        }
+
+        static Platform get() {
+            String osName = GetPropertyAction.privilegedGetProperty("os.name");
+
+            if (osName.equals("Linux")) { return LINUX; }
+            if (osName.contains("OS X")) { return BSD; }
+            if (osName.equals("SunOS")) { return SOLARIS; }
+            if (osName.equals("AIX")) { return AIX; }
+
+            throw new Error(osName + " is not a supported OS platform.");
+        }
+    }
+
+    private static final Platform platform = Platform.get();
+    private static final LaunchMechanism launchMechanism = platform.launchMechanism();
+    private static final byte[] helperpath = toCString(platform.helperPath());
 
     private static byte[] toCString(String s) {
         if (s == null)
             return null;
         byte[] bytes = s.getBytes();
         byte[] result = new byte[bytes.length + 1];
         System.arraycopy(bytes, 0,
                          result, 0,
                          bytes.length);
         result[result.length-1] = (byte)0;
         return result;
     }
 
     // Only for use by ProcessBuilder.start()
     static Process start(String[] cmdarray,
                          java.util.Map<String,String> environment,
                          String dir,
                          ProcessBuilder.Redirect[] redirects,
                          boolean redirectErrorStream)
-        throws IOException
+            throws IOException
     {
         assert cmdarray != null && cmdarray.length > 0;
 
         // Convert arguments to a contiguous block; it's easier to do
         // memory management in Java than in C.
         byte[][] args = new byte[cmdarray.length-1][];
         int size = args.length; // For added NUL bytes
         for (int i = 0; i < args.length; i++) {
             args[i] = cmdarray[i+1].getBytes();
             size += args[i].length;
         }
         byte[] argBlock = new byte[size];
         int i = 0;
         for (byte[] arg : args) {
             System.arraycopy(arg, 0, argBlock, i, arg.length);
             i += arg.length + 1;
             // No need to write NUL bytes explicitly
         }
 
         int[] envc = new int[1];
         byte[] envBlock = ProcessEnvironment.toEnvironmentBlock(environment, envc);
 
         int[] std_fds;
 
         FileInputStream  f0 = null;
         FileOutputStream f1 = null;
         FileOutputStream f2 = null;
 
         try {
+            boolean forceNullOutputStream = false;
             if (redirects == null) {
                 std_fds = new int[] { -1, -1, -1 };
             } else {
                 std_fds = new int[3];
 
-                if (redirects[0] == Redirect.PIPE)
+                if (redirects[0] == Redirect.PIPE) {
                     std_fds[0] = -1;
-                else if (redirects[0] == Redirect.INHERIT)
+                } else if (redirects[0] == Redirect.INHERIT) {
                     std_fds[0] = 0;
-                else {
+                } else if (redirects[0] instanceof ProcessBuilder.RedirectPipeImpl) {
+                    std_fds[0] = fdAccess.get(((ProcessBuilder.RedirectPipeImpl) redirects[0]).getFd());
+                } else {
                     f0 = new FileInputStream(redirects[0].file());
                     std_fds[0] = fdAccess.get(f0.getFD());
                 }
 
-                if (redirects[1] == Redirect.PIPE)
+                if (redirects[1] == Redirect.PIPE) {
                     std_fds[1] = -1;
-                else if (redirects[1] == Redirect.INHERIT)
+                } else if (redirects[1] == Redirect.INHERIT) {
                     std_fds[1] = 1;
-                else {
+                } else if (redirects[1] instanceof ProcessBuilder.RedirectPipeImpl) {
+                    std_fds[1] = fdAccess.get(((ProcessBuilder.RedirectPipeImpl) redirects[1]).getFd());
+                    // Force getInputStream to return a null stream,
+                    // the fd is directly assigned to the next process.
+                    forceNullOutputStream = true;
+                } else {
                     f1 = new FileOutputStream(redirects[1].file(),
-                                              redirects[1].append());
+                            redirects[1].append());
                     std_fds[1] = fdAccess.get(f1.getFD());
                 }
 
-                if (redirects[2] == Redirect.PIPE)
+                if (redirects[2] == Redirect.PIPE) {
                     std_fds[2] = -1;
-                else if (redirects[2] == Redirect.INHERIT)
+                } else if (redirects[2] == Redirect.INHERIT) {
                     std_fds[2] = 2;
-                else {
+                } else if (redirects[2] instanceof ProcessBuilder.RedirectPipeImpl) {
+                    std_fds[2] = fdAccess.get(((ProcessBuilder.RedirectPipeImpl) redirects[2]).getFd());
+                } else {
                     f2 = new FileOutputStream(redirects[2].file(),
-                                              redirects[2].append());
+                            redirects[2].append());
                     std_fds[2] = fdAccess.get(f2.getFD());
                 }
             }
 
-        return new UNIXProcess
-            (toCString(cmdarray[0]),
-             argBlock, args.length,
-             envBlock, envc[0],
-             toCString(dir),
-                 std_fds,
-             redirectErrorStream);
+            Process p = new ProcessImpl
+                    (toCString(cmdarray[0]),
+                            argBlock, args.length,
+                            envBlock, envc[0],
+                            toCString(dir),
+                            std_fds,
+                            forceNullOutputStream,
+                            redirectErrorStream);
+            if (redirects != null) {
+                // Copy the fd's if they are to be redirected to another process
+                if (std_fds[0] >= 0 &&
+                        redirects[0] instanceof ProcessBuilder.RedirectPipeImpl) {
+                    fdAccess.set(((ProcessBuilder.RedirectPipeImpl) redirects[0]).getFd(), std_fds[0]);
+                }
+                if (std_fds[1] >= 0 &&
+                        redirects[1] instanceof ProcessBuilder.RedirectPipeImpl) {
+                    fdAccess.set(((ProcessBuilder.RedirectPipeImpl) redirects[1]).getFd(), std_fds[1]);
+                }
+                if (std_fds[2] >= 0 &&
+                        redirects[2] instanceof ProcessBuilder.RedirectPipeImpl) {
+                    fdAccess.set(((ProcessBuilder.RedirectPipeImpl) redirects[2]).getFd(), std_fds[2]);
+                }
+            }
+            return p;
         } finally {
             // In theory, close() can throw IOException
             // (although it is rather unlikely to happen here)
             try { if (f0 != null) f0.close(); }
             finally {
                 try { if (f1 != null) f1.close(); }
                 finally { if (f2 != null) f2.close(); }
             }
         }
     }
+
+
+    /**
+     * Creates a process. Depending on the {@code mode} flag, this is done by
+     * one of the following mechanisms:
+     * <pre>
+     *   1 - fork(2) and exec(2)
+     *   2 - posix_spawn(3P)
+     *   3 - vfork(2) and exec(2)
+     * </pre>
+     * @param fds an array of three file descriptors.
+     *        Indexes 0, 1, and 2 correspond to standard input,
+     *        standard output and standard error, respectively.  On
+     *        input, a value of -1 means to create a pipe to connect
+     *        child and parent processes.  On output, a value which
+     *        is not -1 is the parent pipe fd corresponding to the
+     *        pipe which has been created.  An element of this array
+     *        is -1 on input if and only if it is <em>not</em> -1 on
+     *        output.
+     * @return the pid of the subprocess
+     */
+    private native int forkAndExec(int mode, byte[] helperpath,
+                                   byte[] prog,
+                                   byte[] argBlock, int argc,
+                                   byte[] envBlock, int envc,
+                                   byte[] dir,
+                                   int[] fds,
+                                   boolean redirectErrorStream)
+        throws IOException;
+
+    private ProcessImpl(final byte[] prog,
+                final byte[] argBlock, final int argc,
+                final byte[] envBlock, final int envc,
+                final byte[] dir,
+                final int[] fds,
+                final boolean forceNullOutputStream,
+                final boolean redirectErrorStream)
+            throws IOException {
+
+        pid = forkAndExec(launchMechanism.ordinal() + 1,
+                          helperpath,
+                          prog,
+                          argBlock, argc,
+                          envBlock, envc,
+                          dir,
+                          fds,
+                          redirectErrorStream);
+        processHandle = ProcessHandleImpl.getInternal(pid);
+
+        try {
+            doPrivileged((PrivilegedExceptionAction<Void>) () -> {
+                initStreams(fds, forceNullOutputStream);
+                return null;
+            });
+        } catch (PrivilegedActionException ex) {
+            throw (IOException) ex.getException();
+        }
+    }
+
+    static FileDescriptor newFileDescriptor(int fd) {
+        FileDescriptor fileDescriptor = new FileDescriptor();
+        fdAccess.set(fileDescriptor, fd);
+        return fileDescriptor;
+    }
+
+    /**
+     * Initialize the streams from the file descriptors.
+     * @param fds array of stdin, stdout, stderr fds
+     * @param forceNullOutputStream true if the stdout is being directed to
+     *        a subsequent process. The stdout stream should be a null output stream .
+     * @throws IOException
+     */
+    void initStreams(int[] fds, boolean forceNullOutputStream) throws IOException {
+        switch (platform) {
+            case LINUX:
+            case BSD:
+                stdin = (fds[0] == -1) ?
+                        ProcessBuilder.NullOutputStream.INSTANCE :
+                        new ProcessPipeOutputStream(fds[0]);
+
+                stdout = (fds[1] == -1 || forceNullOutputStream) ?
+                         ProcessBuilder.NullInputStream.INSTANCE :
+                         new ProcessPipeInputStream(fds[1]);
+
+                stderr = (fds[2] == -1) ?
+                         ProcessBuilder.NullInputStream.INSTANCE :
+                         new ProcessPipeInputStream(fds[2]);
+
+                ProcessHandleImpl.completion(pid, true).handle((exitcode, throwable) -> {
+                    synchronized (this) {
+                        this.exitcode = (exitcode == null) ? -1 : exitcode.intValue();
+                        this.hasExited = true;
+                        this.notifyAll();
+                    }
+
+                    if (stdout instanceof ProcessPipeInputStream)
+                        ((ProcessPipeInputStream) stdout).processExited();
+
+                    if (stderr instanceof ProcessPipeInputStream)
+                        ((ProcessPipeInputStream) stderr).processExited();
+
+                    if (stdin instanceof ProcessPipeOutputStream)
+                        ((ProcessPipeOutputStream) stdin).processExited();
+
+                    return null;
+                });
+                break;
+
+            case SOLARIS:
+                stdin = (fds[0] == -1) ?
+                        ProcessBuilder.NullOutputStream.INSTANCE :
+                        new BufferedOutputStream(
+                            new FileOutputStream(newFileDescriptor(fds[0])));
+
+                stdout = (fds[1] == -1 || forceNullOutputStream) ?
+                         ProcessBuilder.NullInputStream.INSTANCE :
+                         new BufferedInputStream(
+                             stdout_inner_stream =
+                                 new DeferredCloseInputStream(
+                                     newFileDescriptor(fds[1])));
+
+                stderr = (fds[2] == -1) ?
+                         ProcessBuilder.NullInputStream.INSTANCE :
+                         new DeferredCloseInputStream(newFileDescriptor(fds[2]));
+
+                /*
+                 * For each subprocess forked a corresponding reaper task
+                 * is submitted.  That task is the only thread which waits
+                 * for the subprocess to terminate and it doesn't hold any
+                 * locks while doing so.  This design allows waitFor() and
+                 * exitStatus() to be safely executed in parallel (and they
+                 * need no native code).
+                 */
+                ProcessHandleImpl.completion(pid, true).handle((exitcode, throwable) -> {
+                    synchronized (this) {
+                        this.exitcode = (exitcode == null) ? -1 : exitcode.intValue();
+                        this.hasExited = true;
+                        this.notifyAll();
+                    }
+                    return null;
+                });
+                break;
+
+            case AIX:
+                stdin = (fds[0] == -1) ?
+                        ProcessBuilder.NullOutputStream.INSTANCE :
+                        new ProcessPipeOutputStream(fds[0]);
+
+                stdout = (fds[1] == -1 || forceNullOutputStream) ?
+                         ProcessBuilder.NullInputStream.INSTANCE :
+                         new DeferredCloseProcessPipeInputStream(fds[1]);
+
+                stderr = (fds[2] == -1) ?
+                         ProcessBuilder.NullInputStream.INSTANCE :
+                         new DeferredCloseProcessPipeInputStream(fds[2]);
+
+                ProcessHandleImpl.completion(pid, true).handle((exitcode, throwable) -> {
+                    synchronized (this) {
+                        this.exitcode = (exitcode == null) ? -1 : exitcode.intValue();
+                        this.hasExited = true;
+                        this.notifyAll();
+                    }
+
+                    if (stdout instanceof DeferredCloseProcessPipeInputStream)
+                        ((DeferredCloseProcessPipeInputStream) stdout).processExited();
+
+                    if (stderr instanceof DeferredCloseProcessPipeInputStream)
+                        ((DeferredCloseProcessPipeInputStream) stderr).processExited();
+
+                    if (stdin instanceof ProcessPipeOutputStream)
+                        ((ProcessPipeOutputStream) stdin).processExited();
+
+                    return null;
+                });
+                break;
+
+            default: throw new AssertionError("Unsupported platform: " + platform);
+        }
+    }
+
+    public OutputStream getOutputStream() {
+        return stdin;
+    }
+
+    public InputStream getInputStream() {
+        return stdout;
+    }
+
+    public InputStream getErrorStream() {
+        return stderr;
+    }
+
+    public synchronized int waitFor() throws InterruptedException {
+        while (!hasExited) {
+            wait();
+        }
+        return exitcode;
+    }
+
+    @Override
+    public synchronized boolean waitFor(long timeout, TimeUnit unit)
+        throws InterruptedException
+    {
+        long remainingNanos = unit.toNanos(timeout);    // throw NPE before other conditions
+        if (hasExited) return true;
+        if (timeout <= 0) return false;
+
+        long deadline = System.nanoTime() + remainingNanos;
+        do {
+            TimeUnit.NANOSECONDS.timedWait(this, remainingNanos);
+            if (hasExited) {
+                return true;
+            }
+            remainingNanos = deadline - System.nanoTime();
+        } while (remainingNanos > 0);
+        return hasExited;
+    }
+
+    public synchronized int exitValue() {
+        if (!hasExited) {
+            throw new IllegalThreadStateException("process hasn't exited");
+        }
+        return exitcode;
+    }
+
+    private void destroy(boolean force) {
+        switch (platform) {
+            case LINUX:
+            case BSD:
+            case AIX:
+                // There is a risk that pid will be recycled, causing us to
+                // kill the wrong process!  So we only terminate processes
+                // that appear to still be running.  Even with this check,
+                // there is an unavoidable race condition here, but the window
+                // is very small, and OSes try hard to not recycle pids too
+                // soon, so this is quite safe.
+                synchronized (this) {
+                    if (!hasExited)
+                        processHandle.destroyProcess(force);
+                }
+                try { stdin.close();  } catch (IOException ignored) {}
+                try { stdout.close(); } catch (IOException ignored) {}
+                try { stderr.close(); } catch (IOException ignored) {}
+                break;
+
+            case SOLARIS:
+                // There is a risk that pid will be recycled, causing us to
+                // kill the wrong process!  So we only terminate processes
+                // that appear to still be running.  Even with this check,
+                // there is an unavoidable race condition here, but the window
+                // is very small, and OSes try hard to not recycle pids too
+                // soon, so this is quite safe.
+                synchronized (this) {
+                    if (!hasExited)
+                        processHandle.destroyProcess(force);
+                    try {
+                        stdin.close();
+                        if (stdout_inner_stream != null)
+                            stdout_inner_stream.closeDeferred(stdout);
+                        if (stderr instanceof DeferredCloseInputStream)
+                            ((DeferredCloseInputStream) stderr)
+                                .closeDeferred(stderr);
+                    } catch (IOException e) {
+                        // ignore
+                    }
+                }
+                break;
+
+            default: throw new AssertionError("Unsupported platform: " + platform);
+        }
+    }
+
+    @Override
+    public CompletableFuture<Process> onExit() {
+        return ProcessHandleImpl.completion(pid, false)
+                .handleAsync((unusedExitStatus, unusedThrowable) -> {
+                    boolean interrupted = false;
+                    while (true) {
+                        // Ensure that the concurrent task setting the exit status has completed
+                        try {
+                            waitFor();
+                            break;
+                        } catch (InterruptedException ie) {
+                            interrupted = true;
+                        }
+                    }
+                    if (interrupted) {
+                        Thread.currentThread().interrupt();
+                    }
+                    return this;
+                });
+    }
+
+    @Override
+    public ProcessHandle toHandle() {
+        SecurityManager sm = System.getSecurityManager();
+        if (sm != null) {
+            sm.checkPermission(new RuntimePermission("manageProcess"));
+        }
+        return processHandle;
+    }
+
+    @Override
+    public boolean supportsNormalTermination() {
+        return ProcessImpl.SUPPORTS_NORMAL_TERMINATION;
+    }
+
+    @Override
+    public void destroy() {
+        destroy(false);
+    }
+
+    @Override
+    public Process destroyForcibly() {
+        destroy(true);
+        return this;
+    }
+
+    @Override
+    public long pid() {
+        return pid;
+    }
+
+    @Override
+    public synchronized boolean isAlive() {
+        return !hasExited;
+    }
+
+    /**
+     * The {@code toString} method returns a string consisting of
+     * the native process ID of the process and the exit value of the process.
+     *
+     * @return a string representation of the object.
+     */
+    @Override
+    public String toString() {
+        return new StringBuilder("Process[pid=").append(pid)
+                .append(", exitValue=").append(hasExited ? exitcode : "\"not exited\"")
+                .append("]").toString();
+    }
+
+    private static native void init();
+
+    static {
+        init();
+    }
+
+    /**
+     * A buffered input stream for a subprocess pipe file descriptor
+     * that allows the underlying file descriptor to be reclaimed when
+     * the process exits, via the processExited hook.
+     *
+     * This is tricky because we do not want the user-level InputStream to be
+     * closed until the user invokes close(), and we need to continue to be
+     * able to read any buffered data lingering in the OS pipe buffer.
+     */
+    private static class ProcessPipeInputStream extends BufferedInputStream {
+        private final Object closeLock = new Object();
+
+        ProcessPipeInputStream(int fd) {
+            super(new PipeInputStream(newFileDescriptor(fd)));
+        }
+        private static byte[] drainInputStream(InputStream in)
+                throws IOException {
+            int n = 0;
+            int j;
+            byte[] a = null;
+            while ((j = in.available()) > 0) {
+                a = (a == null) ? new byte[j] : Arrays.copyOf(a, n + j);
+                n += in.read(a, n, j);
+            }
+            return (a == null || n == a.length) ? a : Arrays.copyOf(a, n);
+        }
+
+        /** Called by the process reaper thread when the process exits. */
+        synchronized void processExited() {
+            synchronized (closeLock) {
+                try {
+                    InputStream in = this.in;
+                    // this stream is closed if and only if: in == null
+                    if (in != null) {
+                        byte[] stragglers = drainInputStream(in);
+                        in.close();
+                        this.in = (stragglers == null) ?
+                            ProcessBuilder.NullInputStream.INSTANCE :
+                            new ByteArrayInputStream(stragglers);
+                    }
+                } catch (IOException ignored) {}
+            }
+        }
+
+        @Override
+        public void close() throws IOException {
+            // BufferedInputStream#close() is not synchronized unlike most other
+            // methods. Synchronizing helps avoid race with processExited().
+            synchronized (closeLock) {
+                super.close();
+            }
+        }
+    }
+
+    /**
+     * A buffered output stream for a subprocess pipe file descriptor
+     * that allows the underlying file descriptor to be reclaimed when
+     * the process exits, via the processExited hook.
+     */
+    private static class ProcessPipeOutputStream extends BufferedOutputStream {
+        ProcessPipeOutputStream(int fd) {
+            super(new FileOutputStream(newFileDescriptor(fd)));
+        }
+
+        /** Called by the process reaper thread when the process exits. */
+        synchronized void processExited() {
+            OutputStream out = this.out;
+            if (out != null) {
+                try {
+                    out.close();
+                } catch (IOException ignored) {
+                    // We know of no reason to get an IOException, but if
+                    // we do, there's nothing else to do but carry on.
+                }
+                this.out = ProcessBuilder.NullOutputStream.INSTANCE;
+            }
+        }
+    }
+
+    // A FileInputStream that supports the deferment of the actual close
+    // operation until the last pending I/O operation on the stream has
+    // finished.  This is required on Solaris because we must close the stdin
+    // and stdout streams in the destroy method in order to reclaim the
+    // underlying file descriptors.  Doing so, however, causes any thread
+    // currently blocked in a read on one of those streams to receive an
+    // IOException("Bad file number"), which is incompatible with historical
+    // behavior.  By deferring the close we allow any pending reads to see -1
+    // (EOF) as they did before.
+    //
+    private static class DeferredCloseInputStream extends PipeInputStream {
+        DeferredCloseInputStream(FileDescriptor fd) {
+            super(fd);
+        }
+
+        private Object lock = new Object();     // For the following fields
+        private boolean closePending = false;
+        private int useCount = 0;
+        private InputStream streamToClose;
+
+        private void raise() {
+            synchronized (lock) {
+                useCount++;
+            }
+        }
+
+        private void lower() throws IOException {
+            synchronized (lock) {
+                useCount--;
+                if (useCount == 0 && closePending) {
+                    streamToClose.close();
+                }
+            }
+        }
+
+        // stc is the actual stream to be closed; it might be this object, or
+        // it might be an upstream object for which this object is downstream.
+        //
+        private void closeDeferred(InputStream stc) throws IOException {
+            synchronized (lock) {
+                if (useCount == 0) {
+                    stc.close();
+                } else {
+                    closePending = true;
+                    streamToClose = stc;
+                }
+            }
+        }
+
+        public void close() throws IOException {
+            synchronized (lock) {
+                useCount = 0;
+                closePending = false;
+            }
+            super.close();
+        }
+
+        public int read() throws IOException {
+            raise();
+            try {
+                return super.read();
+            } finally {
+                lower();
+            }
+        }
+
+        public int read(byte[] b) throws IOException {
+            raise();
+            try {
+                return super.read(b);
+            } finally {
+                lower();
+            }
+        }
+
+        public int read(byte[] b, int off, int len) throws IOException {
+            raise();
+            try {
+                return super.read(b, off, len);
+            } finally {
+                lower();
+            }
+        }
+
+        public long skip(long n) throws IOException {
+            raise();
+            try {
+                return super.skip(n);
+            } finally {
+                lower();
+            }
+        }
+
+        public int available() throws IOException {
+            raise();
+            try {
+                return super.available();
+            } finally {
+                lower();
+            }
+        }
+    }
+
+    /**
+     * A buffered input stream for a subprocess pipe file descriptor
+     * that allows the underlying file descriptor to be reclaimed when
+     * the process exits, via the processExited hook.
+     *
+     * This is tricky because we do not want the user-level InputStream to be
+     * closed until the user invokes close(), and we need to continue to be
+     * able to read any buffered data lingering in the OS pipe buffer.
+     *
+     * On AIX this is especially tricky, because the 'close()' system call
+     * will block if another thread is at the same time blocked in a file
+     * operation (e.g. 'read()') on the same file descriptor. We therefore
+     * combine 'ProcessPipeInputStream' approach used on Linux and Bsd
+     * with the DeferredCloseInputStream approach used on Solaris. This means
+     * that every potentially blocking operation on the file descriptor
+     * increments a counter before it is executed and decrements it once it
+     * finishes. The 'close()' operation will only be executed if there are
+     * no pending operations. Otherwise it is deferred after the last pending
+     * operation has finished.
+     *
+     */
+    private static class DeferredCloseProcessPipeInputStream
+        extends BufferedInputStream {
+
+        private final Object closeLock = new Object();
+        private int useCount = 0;
+        private boolean closePending = false;
+
+        DeferredCloseProcessPipeInputStream(int fd) {
+            super(new PipeInputStream(newFileDescriptor(fd)));
+        }
+
+        private InputStream drainInputStream(InputStream in)
+                throws IOException {
+            int n = 0;
+            int j;
+            byte[] a = null;
+            synchronized (closeLock) {
+                if (buf == null) // asynchronous close()?
+                    return null; // discard
+                j = in.available();
+            }
+            while (j > 0) {
+                a = (a == null) ? new byte[j] : Arrays.copyOf(a, n + j);
+                synchronized (closeLock) {
+                    if (buf == null) // asynchronous close()?
+                        return null; // discard
+                    n += in.read(a, n, j);
+                    j = in.available();
+                }
+            }
+            return (a == null) ?
+                    ProcessBuilder.NullInputStream.INSTANCE :
+                    new ByteArrayInputStream(n == a.length ? a : Arrays.copyOf(a, n));
+        }
+
+        /** Called by the process reaper thread when the process exits. */
+        synchronized void processExited() {
+            try {
+                InputStream in = this.in;
+                if (in != null) {
+                    InputStream stragglers = drainInputStream(in);
+                    in.close();
+                    this.in = stragglers;
+                }
+            } catch (IOException ignored) { }
+        }
+
+        private void raise() {
+            synchronized (closeLock) {
+                useCount++;
+            }
+        }
+
+        private void lower() throws IOException {
+            synchronized (closeLock) {
+                useCount--;
+                if (useCount == 0 && closePending) {
+                    closePending = false;
+                    super.close();
+                }
+            }
+        }
+
+        @Override
+        public int read() throws IOException {
+            raise();
+            try {
+                return super.read();
+            } finally {
+                lower();
+            }
+        }
+
+        @Override
+        public int read(byte[] b) throws IOException {
+            raise();
+            try {
+                return super.read(b);
+            } finally {
+                lower();
+            }
+        }
+
+        @Override
+        public int read(byte[] b, int off, int len) throws IOException {
+            raise();
+            try {
+                return super.read(b, off, len);
+            } finally {
+                lower();
+            }
+        }
+
+        @Override
+        public long skip(long n) throws IOException {
+            raise();
+            try {
+                return super.skip(n);
+            } finally {
+                lower();
+            }
+        }
+
+        @Override
+        public int available() throws IOException {
+            raise();
+            try {
+                return super.available();
+            } finally {
+                lower();
+            }
+        }
+
+        @Override
+        public void close() throws IOException {
+            // BufferedInputStream#close() is not synchronized unlike most other
+            // methods. Synchronizing helps avoid racing with drainInputStream().
+            synchronized (closeLock) {
+                if (useCount == 0) {
+                    super.close();
+                }
+                else {
+                    closePending = true;
+                }
+            }
+        }
+    }
 }